Micro LED micro display array chip and micro projection system

Abstract

The application discloses a Micro LED micro display array chip and a micro projection system, and belongs to the technical field of semiconductor micro display, and comprises a square combined color prism group which is formed by splicing four independent three-prism prisms and is respectively a green light incident prism, a red light incident prism, a blue light incident prism and an out-light prism; the Micro LED micro display array chip is attached to the light incident surface of the combined color prism group and comprises a green Micro LED micro display array chip, a red Micro LED micro display array chip and a blue Micro LED micro display array chip; a light projection part is located outside the light exit surface of the combined color prism group and coincides with the optical axis of the out-light prism; and the application solves the technical problems of a full-color image blur, excessive light crosstalk between pixels, a low yield of mass transfer finished products and an excessively large electrode occupied area of three primary color image synthesis of the Micro LED micro display chip.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of semiconductor micro display, and particularly relates to a Micro LED micro display array chip and a micro projection system. BACKGROUND

[0002] Micro LED micro display technology is a display technology based on micro light-emitting diodes. The size of a single Micro LED pixel point reaches microns, and the high-density Micro LED of micron size is integrated on a chip. A single micron-sized LED can be independently controlled as a pixel point, and the required image is generated by adjusting a single micron-sized LED. Micro LED micro display has the advantages of high brightness, high contrast, low power consumption, rich color, fast response speed, etc. Micro LED micro display technology has broad application prospects in micro projectors and small-area display applications such as augmented reality (AR), virtual reality (VR), wearable optoelectronic display devices, etc. due to its unique advantages.

[0003] AR glasses (Augmented Reality Glasses) are a wearable optoelectronic display device based on augmented reality technology. Its function is to project virtual objects or information into the real world. It has a variety of application scenarios, including entertainment, education, medical care, industry, military, etc. Currently, AR micro displays need to have high enough resolution and pixel density, good contrast and color performance in order to provide clear and realistic images when viewed at close range, display real and vivid scenes, and enhance the user's visual experience.

[0004] The mainstream AR glasses solutions today are video see-through and optical see-through. Optical see-through AR head-mounted display devices were first developed by Ivan Edward Sutherland, the father of computer graphics, in 1968. Optical see-through AR glasses are attracting attention due to their small size, light weight, and convenient wear. The mainstream optical see-through AR glasses use a micro projector as the image source. By adjusting the projector, the image quality can be improved, and the flexibility is high. In the micro projector, 3LCD (three-piece liquid crystal display technology) micro projectors are favored by major manufacturers. 3LCD projection technology was first introduced by Epson in 1996. Thanks to the three independent LCD panels of 3LCD micro projectors, the brightness and contrast of each color channel can be easily adjusted, so the projection effect is very good and can reproduce very realistic colors. Under the same wattage, 3LCD micro projectors have higher ANSI lumen output.

[0005] Micro LED brings new ideas to micro projection technology. Compared with traditional 3LCD display technology, Micro LED micro display has higher brightness, higher resolution, higher contrast, richer color, faster response time and lower power consumption. Using Micro LED micro display array chip as the image source of micro projector will be more conducive to improving the output brightness, resolution, contrast and other parameters of micro projector, and bringing better experience to users.

[0006] However, there are still many problems in using Micro LED micro display array chip as the image source of micro projection system at present, and there are some challenges, which limit its large-scale application. The main problems are as follows:

[0007] Firstly, when three independent Micro LED micro display array chips are combined into a color image, the precise alignment of the image and the light path cannot be guaranteed, and pixel displacement phenomenon occurs, resulting in misregistration and overlapping of color image, which leads to image blur;

[0008] Secondly, when the Micro LED micro display array chip substrate emits light, there is still light crosstalk between each pixel point, which affects the light emission efficiency and thus affects the display effect;

[0009] Thirdly, generally, Micro LED micro display array chip has a large number of pixel points. The yield of the mass transfer scheme of transferring a single Micro LED pixel to the driving substrate is low, the efficiency is low, and the process difficulty is great;

[0010] Fourthly, generally, the N electrodes of Micro LED micro display array chip occupy a large area of the chip, which leads to relatively low integration and resolution of the array chip. SUMMARY

[0011] The purpose of the present application is to provide a Micro LED micro display array chip and a micro projection system to solve the technical problems of the full-color image blur of three primary color image synthesis of the existing Micro LED micro display chip, excessive pixel-to-pixel light crosstalk, low yield of mass transfer, and excessive electrode area occupation in the background art.

[0012] In order to achieve the above purpose, the present application provides the following technical solutions:

[0013] A Micro LED micro display array chip, comprising a substrate, a buffer layer on the upper surface of the substrate, a common N-pole high-doped conductive layer on the upper surface of the buffer layer, an N-type electron injection layer on the upper surface of the common N-pole high-doped conductive layer, a multi-quantum well active region on the upper surface of the N-type electron injection layer, a P-type hole injection layer on the upper surface of the multi-quantum well active region, a transparent electrode layer on the upper surface of the P-type hole injection layer, an insulating layer filled between the upper surface of both ends of the common N-pole high-doped conductive layer of the Micro LED micro display array chip and a single pixel, a common P-contact electrode on both ends of the transparent electrode layer, a common P-pole metal conductive layer filled inside a P-pole via hole passing through the substrate and the insulating layer on the lower surface of the common P-contact electrode, a common P-pole via hole electrode on the lower surface of the common P-pole metal conductive layer, a common N-pole metal conductive layer filled inside an N-pole via hole passing through the buffer layer and the substrate on the lower surface of both ends of the common N-pole high-doped conductive layer, a common N-pole via hole electrode on the lower surface of the common N-pole metal conductive layer, and a light-transmitting protective layer grown on the upper surface of the array.

[0014] A miniature projection system based on a monolithic Micro LED micro display array chip, comprising:

[0015] A cubic color-combining prism group composed of four independent triple prisms, wherein the four triple prisms are a green light incident prism, a red light incident prism, a blue light incident prism, and an outgoing light prism.

[0016] A Micro LED micro display array chip attached to the light-incident surface of the color-combining prism group, wherein the micro display array chip comprises a green Micro LED micro display array chip attached to the light-incident surface of the green light incident prism, a red Micro LED micro display array chip attached to the light-incident surface of the red light incident prism, and a blue Micro LED micro display array chip attached to the light-incident surface of the blue light incident prism.

[0017] A light projection part located outside the outgoing light surface of the color-combining prism group and coinciding with the optical axis of the outgoing light prism.

[0018] The Micro LED pixel array of the green Micro LED micro display array chip, the red Micro LED micro display array chip and the blue Micro LED micro display array chip is integrated monolithic processing, the pixel array uses a common original substrate of LEDs, and no single-pixel cutting and separation is performed, the substrate is prepared by epitaxial growth to have a common N-pole high-doped conductive layer, the common N-pole high-doped conductive layer of the row pixels is used as a common N electrode, the column pixels use a transparent electrode layer as a common P electrode, a common P contact electrode is led out by the common P electrode, and the micro display array emits light through the transparent electrode layer; the structure of front light emission is adopted to avoid the phenomenon that light emitted by the substrate propagates in the form of waveguide, improve light emission efficiency, and improve light crosstalk phenomenon; the buffer layer of the Micro LED micro display array chip is etched to the substrate along with the common N-pole high-doped conductive layer, and has the same etching shape.

[0019] Preferably, a common N-pole via electrode is prepared at a position corresponding to the common N electrode leading-out point on the back of the substrate of the micro display array chip, and a common P-pole via electrode is prepared at a position corresponding to the common P contact electrode leading-out point, and the row and column scanning electrodes form a micro display array driving interface through the via electrode on the back of the substrate; the micro display array chip is connected with a micro display driving substrate to display an image through a driving system, so that the monolithic Micro LED micro display array chip is prevented from being blocked by the contact electrode when being attached or installed with the incident prism, and the connection between the contact electrode and the driving interface is affected.

[0020] Preferably, the green Micro LED micro display array chip, the red Micro LED micro display array chip and the blue Micro LED micro display array chip have the same geometric size structure, and are provided with an image alignment pattern and an array light path alignment pattern on the surface; the array light path alignment pattern is used for accurate attachment with a color combining prism group, and the image alignment pattern is used for light path alignment of the three-color Micro LED micro display array chip, so as to ensure accurate superposition of three-color micro display images and combination into a color image.

[0021] Preferably, a prism light path alignment pattern is arranged on the light incident surface of the green light incident prism, the red light incident prism and the blue light incident prism.

[0022] Preferably, the red light incident prism is located between the green light incident prism and the blue light incident prism, a green light reflecting film is arranged on the attachment surface of the green light incident prism and the red light incident prism; a blue light reflecting film is arranged on the attachment surface of the red light incident prism and the blue light incident prism; a blue light reflecting film is arranged on the attachment surface of the green light incident prism and the light emitting prism; and a green light reflecting film is arranged on the attachment surface of the blue light incident prism and the light emitting prism.

[0023] Preferably, the green light incident prism is located between the red light incident prism and the blue light incident prism, a red light reflecting film is arranged on the abutting surface of the red light incident prism and the green light incident prism; a blue light reflecting film is arranged on the abutting surface of the green light incident prism and the blue light incident prism; a blue light reflecting film is arranged on the abutting surface of the red light incident prism and the light output prism; and a red light reflecting film is arranged on the abutting surface of the green light incident prism and the light output prism.

[0024] Preferably, the blue light incident prism is located between the green light incident prism and the red light incident prism, a red light reflecting film is arranged on the abutting surface of the red light incident prism and the blue light incident prism; a green light reflecting film is arranged on the abutting surface of the green light incident prism and the blue light incident prism; a green light reflecting film is arranged on the abutting surface of the red light incident prism and the light output prism; and a red light reflecting film is arranged on the abutting surface of the green light incident prism and the light output prism.

[0025] Preferably, the green light reflecting film reflects green light, and transmits blue light and red light; the blue light reflecting film reflects blue light, and transmits red light and green light; the red light reflecting film reflects red light, and transmits blue light and green light; the color combination prism group coincides with the optical axis of the light projection part; and the full-color image output by the light output prism is output to the display area by the light projection part.

[0026] A preparation process of a micro projection system based on a single-chip Micro LED micro display array chip, comprising:

[0027] S1, the green Micro LED micro display array chip, the red Micro LED micro display array chip, and the blue Micro LED micro display array chip are respectively attached to the light-incident surfaces of the green light incident prism, the red light incident prism, and the blue light incident prism according to the array light path alignment pattern on the Micro LED micro display array chip and the prism light path alignment pattern on the incident prism;

[0028] S2, a green light reflecting film is arranged on the abutting surface of the green light incident prism and the red light incident prism; a blue light reflecting film is arranged on the abutting surface of the red light incident prism and the blue light incident prism; a blue light reflecting film is arranged on the abutting surface of the green light incident prism and the light output prism; and a green light reflecting film is arranged on the abutting surface of the blue light incident prism and the light output prism;

[0029] or, a red light reflecting film is arranged on the abutting surface of the red light incident prism and the green light incident prism; a blue light reflecting film is arranged on the abutting surface of the green light incident prism and the blue light incident prism; a blue light reflecting film is arranged on the abutting surface of the red light incident prism and the light output prism; and a red light reflecting film is arranged on the abutting surface of the green light incident prism and the light output prism;

[0030] Or, a red light reflection film is arranged on the bonding surface of the red light incident prism and the blue light incident prism; a green light reflection film is arranged on the bonding surface of the blue light incident prism and the green light incident prism; a green light reflection film is arranged on the bonding surface of the red light incident prism and the light output prism; and a red light reflection film is arranged on the bonding surface of the green light incident prism and the light output prism.

[0031] S3, the green light incident prism, the red light incident prism, the blue light incident prism and the light output prism which are attached with the Micro LED micro display array chip and the reflection film are combined into a color combination prism group, the positions of the green light incident prism, the red light incident prism, the blue light incident prism and the light output prism are adjusted according to the image alignment mark of the Micro LED micro display array chip, so that the green, red and blue images output by the light output prism are overlapped;

[0032] S4, the fixing of the green Micro LED micro display array chip, the red Micro LED micro display array chip, the blue Micro LED micro display array chip and the color combination prism group is completed;

[0033] S5, the lens position of the light projection part is adjusted, so that the image output by the light output prism and the light projection part are coaxial;

[0034] S6, a display array driving interface is reserved, and the green Micro LED micro display array chip, the red Micro LED micro display array chip, the blue Micro LED micro display array chip, the color combination prism group and the light projection part are packaged to form a micro projection system.

[0035] Compared with the prior art, the beneficial effects of the present application are:

[0036] 1. The present application solves the problem that when three independent Micro LED micro display array chips are combined into a color image, the accurate alignment of the image and the light path cannot be guaranteed, pixel displacement occurs, color images are overlapped, and the image is blurred. In the present application, image alignment patterns and array light path alignment patterns are arranged on the surface of the Micro LED micro display array chip; prism light path alignment patterns are arranged on the surface of the color combination prism group; the shape, size, position and other parameters of these marks are accurately matched, and through the alignment patterns during assembly, the accurate bonding or installation of the three-color Micro LED micro display array chip and the color combination prism can be realized; the three primary color images are accurately overlapped, pixel displacement is avoided, the imaging quality is guaranteed, and the display effect will not appear image blur;

[0037] 2. The Micro LED micro display array chip of the application solves the problem of light crosstalk between each pixel point when the substrate of the Micro LED micro display array chip emits light, adopts a vertical structure, emits light from the front instead of the substrate, thereby avoiding the problem of light crosstalk and low light emission efficiency caused by the substrate as the light emitting surface, and ensuring that each pixel point can produce clear and independent light output, and the display quality is improved.

[0038] 3. The Micro LED micro display array chip of the application solves the problems of low yield, low efficiency and high process difficulty of the massive transfer scheme of single Micro LED pixel transferred to the driving substrate; in the application, the Micro LED pixel array of the single-chip Micro LED micro display array chip is integrated single-chip processing, the pixel array uses a common original substrate of LEDs, and single-pixel cutting and separation are not performed, thereby avoiding the massive transfer problem, effectively improving the yield and efficiency, and reducing the process difficulty.

[0039] 4. The Micro LED micro display array chip of the application solves the problem of relatively low integration and resolution of the array chip caused by the large occupation of the chip area by N electrodes, and the application adopts a common N-pole high-doped conductive layer to lead out the N electrode, thereby avoiding the occupation of the chip area by the N electrode on the light emitting surface and improving the integration and resolution of the device. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 FIG. 1 is a schematic diagram of a lateral display array cross-sectional structure of a single-chip Micro LED micro display array chip in a preferred embodiment of the application;

[0041] Figure 2 FIG. 2 is a schematic diagram of a longitudinal display array cross-sectional structure of a single-chip Micro LED micro display array chip in a preferred embodiment of the application;

[0042] Figure 3 FIG. 3 is a schematic diagram of the structure of a triangular prism in a preferred embodiment of the application;

[0043] Figure 4 FIG. 4 is a schematic diagram of the overall structure of a color combining prism group in a preferred embodiment of the application;

[0044] Figure 5 FIG. 5 is a schematic diagram of the positions of an incident prism and a reflective film of a color combining prism group in a preferred embodiment of the application;

[0045] Figure 6 FIG. 6 is a side view of a color combining prism group in a preferred embodiment of the application;

[0046] Figure 7 FIG. 7 is a schematic diagram of a micro projection system based on a single-chip Micro LED micro display array chip in a preferred embodiment of the application;

[0047] Figure 8 Front view of a monolithic Micro LED micro display array chip in a preferred embodiment of the present application;

[0048] Figure 9 Back view of a monolithic Micro LED micro display array chip in a preferred embodiment of the present application;

[0049] Figure 10 Schematic diagram of a monolithic Micro LED micro display array chip and a prism light entrance surface in a preferred embodiment of the present application;

[0050] Figure 11 Cross-sectional view of an AR glasses based on a monolithic Micro LED micro display array chip in a preferred embodiment of the present application;

[0051] Figure 12 Front view of a two-dimensional diffraction optical waveguide of an AR glasses based on a monolithic Micro LED micro display array chip in a preferred embodiment of the present application.

[0052] In the figure: 1, a color combining prism group; 2, a green Micro LED micro display array chip; 3, a red Micro LED micro display array chip; 4, a blue Micro LED micro display array chip; 5, a light projection part; 6, a collimated light path; 7, a diffraction optical waveguide; 8, a light receiving part; 1-1, a green light entrance prism; 1-2, a red light entrance prism; 1-3, a blue light entrance prism; 1-4, an exit light prism; 1-5, a prism light path alignment pattern; 2-1, a substrate; 2-2, a buffer layer; 2-3, a common N-pole high-doped conductive layer; 2-4, an N-type electron injection layer; 2-5, a multi-quantum well active region; 2-6, a P-type hole injection layer; 2-7, a transparent electrode layer; 2-8, an insulating layer; 2-9, a common P-contact electrode; 2-10, a common P-pole metal conductive layer; 2-11, a common P-pole via electrode; 2-12, a common N-pole metal conductive layer; 2-13, a common N-pole via electrode; 2-14, a light-transmitting protective layer; 2-15, an image alignment pattern; 2-16, an array light path alignment pattern; 7-1, a coupling-in grating; 7-2, a planar optical waveguide; 7-3, a coupling-out grating. DETAILED DESCRIPTION

[0053] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative labor fall within the scope of the present application.

[0054] As Figures 1-12 shown:

[0055] First preferred embodiment:

[0056] Referring to Figure 1 A Micro LED micro display array chip, comprising a substrate 2-1, a buffer layer 2-2 on the upper surface of the substrate 2-1, a common N-pole high-doped conductive layer 2-3 on the upper surface of the buffer layer, an N-type electron injection layer 2-4 on the upper surface of the common N-pole high-doped conductive layer 2-3, a multi-quantum well active region 2-5 on the upper surface of the N-type electron injection layer 2-4, a P-type hole injection layer 2-6 on the upper surface of the multi-quantum well active region 2-5, a transparent electrode layer 2-7 on the upper surface of the P-type hole injection layer 2-6, an insulating layer 2-8 filled between the upper surfaces of both ends of the common N-pole high-doped conductive layer 2-3 of the Micro LED micro display array chip and a single pixel, a common P-pole contact electrode 2-9 on both ends of the transparent electrode layer 2-7, a common P-pole metal conductive layer 2-10 filled in the inside of a P-pole via hole passing through the substrate 2-1 and the insulating layer 2-8 on the lower surface of the common P-pole contact electrode 2-9, a common P-pole via hole electrode 2-11 on the lower surface of the common P-pole metal conductive layer 2-10, a common N-pole metal conductive layer 2-12 filled in the inside of an N-pole via hole passing through the buffer layer 2-2 and the substrate 2-1 on the lower surface of both ends of the common N-pole high-doped conductive layer 2-3, a common N-pole via hole electrode 2-13 on the lower surface of the common N-pole metal conductive layer 2-12, and a light-transmitting protective layer 2-14 grown on the upper surface of the array.

[0057] The array chip has an overall size of 2016 μm x 2016 μm and is composed of 64 x 64 Micro LEDs with a size of microns.

[0058] In this embodiment, the array chip has an overall size of 2016 μm x 2016 μm and is composed of 64 x 64 Micro LEDs with a size of microns. The single pixel of the monolithic Micro LED micro display array chip has a size of 20 μm x 20 μm, and the interval between the pixel and its adjacent pixel is 8 μm.

[0059] The green Micro LED micro display array chip 2, the red Micro LED micro display array chip 3, and the blue Micro LED micro display array chip 4 have basically the same structure, except for the material difference. The Micro LED pixel array of the monolithic Micro LED micro display array chip is integrated and processed, the pixel array uses the common original substrate 2-1 of the LED, and no single-pixel cutting and separation is performed. The overall structure of the monolithic Micro LED micro display array chip is more stable, and the problems of low yield and complex process caused by the massive transfer of single chips are avoided.

[0060] By precisely controlling the thickness, proportion, and distribution of the multi-quantum well of different material systems, the wavelength of light emission is adjusted, and the Micro LED micro display array chips with main wavelengths of green, red, and blue are prepared, respectively.

[0061] The chip adopts a front light-out structure, emits light through the transparent electrode layer 2-7, avoids the phenomenon of light propagating in the form of a waveguide caused by light emitted from the substrate 2-1, improves the light-out efficiency, and improves the light crosstalk phenomenon;

[0062] The chip adopts a common N-pole high-doped conductive layer 2-3, and the substrate 2-1 is prepared by an epitaxial growth method to have a common N-pole high-doped conductive layer. The common N-pole high-doped conductive layer adopts a common N-pole structure, and the N electrode is not separately led out in units of single pixel units. Each row of Micro LED pixel units shares an N electrode, and the row pixels share the common N-pole high-doped conductive layer 2-3 as a common N electrode. The column pixels use the transparent electrode layer 2-7 as a common P electrode, and the common P contact electrode 2-9 is led out from the common P electrode. This avoids the N electrode on the light-out surface from occupying the chip area, improves the device integration and resolution.

[0063] The chip substrate back surface is made of a through-hole electrode. The common N-pole through-hole electrode 2-13 is prepared at a position corresponding to the common N electrode lead-out point on the back surface of the substrate 2-1 of the micro display array chip, and the common P-pole through-hole electrode 2-11 is prepared at a position corresponding to the common P contact electrode 2-9 lead-out point. The row and column scan electrodes form a micro display array driving interface through the through-hole electrode on the substrate back surface.

[0064] Each single pixel point in the Micro LED micro display array chip is formed by regionalized pattern etching and is isolated from each other by an insulating layer 2-8, so as to prevent current leakage and interference between different pixel points and ensure that each pixel point can work independently.

[0065] Specifically, the region of a single pixel point is defined in the epitaxially grown semiconductor material layer through an etching process. After the single pixel point is etched, SiO2 insulating layer 2-8 is filled between adjacent pixel points, so that each pixel point is wrapped and isolated by the SiO2 insulating layer 2-8. The entire display array is divided into independent single pixel units, avoiding current leakage and light crosstalk between adjacent pixel points, thereby improving the display effect.

[0066] Second preferred embodiment:

[0067] Please refer to Figures 2-9 A micro projection system based on a single-chip Micro LED micro display array chip, comprising:

[0068] A square cube color prism group 1 composed of four independent triangular prisms. The four triangular prisms are a green light incident prism 1-1, a red light incident prism 1-2, a blue light incident prism 1-3, and a light-out prism 1-4.

[0069] The Micro LED micro display array chip is attached to the light entrance surface of the color combining prism group 1, and the Micro LED micro display array chip includes a green Micro LED micro display array chip 2 attached to the light entrance surface of the green light entrance prism 1-1, a red Micro LED micro display array chip 3 attached to the light entrance surface of the red light entrance prism 1-2, and a blue Micro LED micro display array chip 4 attached to the light entrance surface of the blue light entrance prism 1-3;

[0070] Specifically, a through-hole electrode is prepared at a position corresponding to the row electrode and column electrode lead-out point on the back surface of the substrate 2-1 of the micro display array chip, and the row and column scanning electrodes form a micro display array driving interface through the through-hole electrode on the back surface of the substrate 2-1; the micro display driving substrate is connected, and the image is displayed through the driving system, so that when the monolithic Micro LED micro display array chip is attached or installed with the entrance prism, the contact electrode is prevented from being blocked, and the connection of the contact electrode and the driving interface is affected.

[0071] The green Micro LED micro display array chip 2, the red Micro LED micro display array chip 3, and the blue Micro LED micro display array chip 4 have the same geometric size structure, and the surface is provided with an image alignment pattern 2-15 and an array light path alignment pattern 2-16. The array light path alignment pattern 2-16 is used for accurate attachment with the color combining prism group 1, and the image alignment pattern 2-15 is used for light path alignment of the three-color Micro LED micro display array chip, so as to ensure accurate superposition of the three-color micro display image and synthesis of a color image.

[0072] A light projection part 5 is located outside the light exit surface of the color combining prism group 1 and coincides with the optical axis of the light exit prism 1-4; wherein:

[0073] The Micro LED pixel array of the green Micro LED micro display array chip 2, the red Micro LED micro display array chip 3, and the blue Micro LED micro display array chip 4 is integrated and processed as a monolithic, the pixel array uses a common original substrate of LEDs, without single-pixel cutting and separation, the substrate is prepared with a common N-pole high-doped conductive layer 2-3 by epitaxial growth, the row pixels share the common N-pole high-doped conductive layer 2-3 as a common N electrode, the column pixels use a transparent electrode layer 2-7 as a common P electrode, a common P contact electrode 2-9 is led out by the common P electrode, and the micro display array emits light through the transparent electrode layer 2-7; the structure of front light emission is adopted to avoid the phenomenon that the light emitted by the substrate 2-1 propagates in the form of waveguide, improve the light emission efficiency, and improve the light crosstalk phenomenon; the buffer layer 2-2 of the Micro LED micro display array chip is etched to the substrate 2-1 together with the common N-pole high-doped conductive layer 2-3, and has the same etching shape.

[0074] Further, in actual use, the pixel-shared common N-pole high-doped conductive layer 2-3 can also be used as a common N electrode, and the transparent electrode layer 2-7 can be used as a common P electrode.

[0075] The red light incident prism 1-2 is located between the green light incident prism 1-1 and the blue light incident prism 1-3, and a green light reflection film is arranged on the abutting surface of the green light incident prism 1-1 and the red light incident prism 1-2; a blue light reflection film is arranged on the abutting surface of the red light incident prism 1-2 and the blue light incident prism 1-3; a blue light reflection film is arranged on the abutting surface of the green light incident prism 1-1 and the light output prism 1-4; and a green light reflection film is arranged on the abutting surface of the blue light incident prism 1-3 and the light output prism 1-4. In the embodiment, the incident prisms are arranged in the above order, and in actual application, the order of the three incident prisms can be changed, and the reflection films are adjusted accordingly: the green light incident prism 1-1 is located between the red light incident prism 1-2 and the blue light incident prism 1-3, a red light reflection film is arranged on the abutting surface of the red light incident prism 1-2 and the green light incident prism 1-1; a blue light reflection film is arranged on the abutting surface of the green light incident prism 1-1 and the blue light incident prism 1-3; a blue light reflection film is arranged on the abutting surface of the red light incident prism 1-2 and the light output prism 1-4; and a red light reflection film is arranged on the abutting surface of the blue light incident prism 1-3 and the light output prism 1-4. Or the blue light incident prism 1-3 is located between the green light incident prism 1-1 and the red light incident prism 1-2, a red light reflection film is arranged on the abutting surface of the red light incident prism 1-2 and the blue light incident prism 1-3; a green light reflection film is arranged on the abutting surface of the blue light incident prism 1-3 and the green light incident prism 1-1; a green light reflection film is arranged on the abutting surface of the red light incident prism 1-2 and the light output prism 1-4; and a red light reflection film is arranged on the abutting surface of the green light incident prism 1-1 and the light output prism 1-4.

[0076] The green light reflection film reflects green light and transmits blue light and red light; the blue light reflection film reflects blue light and transmits red light and green light; the red light reflection film reflects red light and transmits blue light and green light, and the full-color image output by the light output prism 1-4 is output to the display area by the light projection part 5.

[0077] The image alignment patterns 2-15 on the three-color Micro LED micro display array chips are matched, which are used to accurately align the display images of the three-color Micro LED micro display array chips to synthesize accurate color images; the shapes, sizes, positions and other parameters of the prism light path alignment patterns 1-5 on the color combining prism group 1 are matched, which are used to accurately abut or mount the three-color Micro LED micro display array chips with the color combining prism group 1, to ensure that the light paths coincide, so as to ensure the imaging quality.

[0078] The Micro LED micro display array chip needs to be precisely aligned and assembled with other optical elements such as the color combining prism group 1 and the Micro LED micro display array chip to correctly image and display, and if the alignment position deviates, it will cause problems such as decline in imaging quality and image blur; in order to precisely align, some special patterns are etched on the surface of the Micro LED micro display array chip and the prism, and the present embodiment adopts a cross mark as the light path alignment pattern, and a scale line as the image alignment pattern 2-15, the positions and sizes of these marks are precisely designed and can be used as a reference during alignment; during assembly, these marks can be observed through a microscope or other devices, and the position of the Micro LED micro display array chip is precisely adjusted to the position where the alignment pattern of the other Micro LED micro display array chip or optical element is overlapped; after the pattern alignment is completed, the precise assembly of the Micro LED micro display array chip and other optical elements can be ensured, thereby obtaining an ideal imaging effect.

[0079] The alignment process of the prism light path alignment pattern 1-5 of the color combining prism group 1 and the image alignment pattern 2-15 and the array light path alignment pattern 2-16 of the three-color Micro LED micro display array chip is as follows: first, the array light path alignment pattern 2-16 on the surface of the green Micro LED micro display array 2, the red Micro LED micro display array chip 3 and the blue Micro LED micro display array chip 4 is aligned and attached or installed with the prism light path alignment pattern 1-5 on the incident surface of the green incident prism 1-1, the red light incident prism 1-2 and the blue light incident prism 1-3 of the color combining prism group 1; then, the image alignment pattern 2-15 on the surface of the green Micro LED micro display array chip 2, the red Micro LED micro display array chip 3 and the blue Micro LED micro display array chip 4 is aligned.

[0080] Third preferred embodiment:

[0081] Please refer to Figures 10-12 A preparation process of a micro projection system based on a single-chip Micro LED micro display chip, comprising:

[0082] S1, the green Micro LED micro display array chip 2, the red Micro LED micro display array chip 3 and the blue Micro LED micro display array chip 4 are respectively attached to the green light incident prism 1-1, the red light incident prism 1-2 and the blue light incident prism 1-3 according to the array light path alignment pattern 2-16 on the Micro LED micro display array chip and the prism light path alignment pattern 1-5 on the incident prism;

[0083] S2, a green light reflecting film is arranged on the bonding surface of the green light incident prism 1-1 and the red light incident prism 1-2; a blue light reflecting film is arranged on the bonding surface of the red light incident prism 1-2 and the blue light incident prism 1-3; a blue light reflecting film is arranged on the bonding surface of the green light incident prism 1-1 and the light output prism 1-4; and a green light reflecting film is arranged on the bonding surface of the blue light incident prism 1-3 and the light output prism 1-4;

[0084] Or, a red light reflecting film is arranged on the bonding surface of the red light incident prism 1-2 and the green light incident prism 1-1; a blue light reflecting film is arranged on the bonding surface of the green light incident prism 1-1 and the blue light incident prism 1-3; a blue light reflecting film is arranged on the bonding surface of the red light incident prism 1-2 and the light output prism 1-4; and a red light reflecting film is arranged on the bonding surface of the blue light incident prism 1-3 and the light output prism 1-4;

[0085] Or, a red light reflecting film is arranged on the bonding surface of the red light incident prism 1-2 and the blue light incident prism 1-3; a green light reflecting film is arranged on the bonding surface of the blue light incident prism 1-3 and the green light incident prism 1-1; a green light reflecting film is arranged on the bonding surface of the red light incident prism 1-2 and the light output prism 1-4; and a red light reflecting film is arranged on the bonding surface of the green light incident prism 1-1 and the light output prism 1-4;

[0086] S3, the green light incident prism 1-1, the red light incident prism 1-2, the blue light incident prism 1-3 and the light output prism 1-4 with the Micro LED micro display array chip and the reflecting film are combined to form a color combination prism group 1, the positions of the green light incident prism 1-1, the red light incident prism 1-2, the blue light incident prism 1-3 and the light output prism 1-4 are adjusted according to the image alignment mark of the Micro LED micro display array chip, so that the green, red and blue images output by the light output prism 1-4 are overlapped;

[0087] S4, the fixing of the green Micro LED micro display array chip 2, the red Micro LED micro display array chip 3, the blue Micro LED micro display array chip 4 and the color combination prism group 1 is completed;

[0088] S5, the lens position of the light projection part 5 is adjusted so that the image output by the light output prism 1-4 and the light projection part 5 are coaxial;

[0089] S6, a display array driving interface is reserved, and the green Micro LED micro display array chip 2, the red Micro LED micro display array chip 3, the blue Micro LED micro display array chip 4, the color combination prism group 1 and the light projection part 5 are packaged to form a micro projection system.

[0090] Fourth preferred embodiment:

[0091] An AR glasses based on a micro projection system design of a single-chip Micro LED micro display array chip, comprising:

[0092] A micro projection system based on a single-chip Micro LED micro display array chip;

[0093] A collimating light path 6 located in front of the micro projection system based on a single-chip Micro LED micro display array chip, which collimates the divergent imaging light into an approximately parallel light beam through the focusing effect of the collimating light path 6, and prepares for subsequent light path transmission; specifically, the micro projection system based on a single-chip Micro LED micro display array chip is the image source of the entire AR glasses; the collimating light path 6 collimates the divergent light from the light projection part 5 into a nearly parallel light beam, and prepares for subsequent coupling to the waveguide;

[0094] A diffractive optical waveguide 7 located in front of the collimating light path 6, which is used to couple the collimated image light into the waveguide and transmit in the waveguide, and finally exit from the out-coupling grating 7-3 and enter the light receiving part 8; the diffractive optical waveguide includes a planar optical waveguide 7-2 for guiding light to the out-coupling grating 7-3 using the principle of total internal reflection; the in-coupling grating 7-1 located on the left side of the planar optical waveguide couples the collimated parallel light into the waveguide at a certain angle through the diffraction effect of the grating; the out-coupling grating 7-3 located on the right side of the optical waveguide couples the light transmitted in the waveguide out at a certain angle through the diffraction effect of the grating to form an image in the light receiving part 8; wherein,

[0095] The optical axes of the color combining prism 1, the light projection part 5, the collimating light path 6, and the in-coupling grating 7-1 coincide, which can avoid defects such as aberration and detuning, and ensure that the image is clear enough.

[0096] The diffractive optical waveguide 7 uses transparent glass material to form a total reflection light transmission channel, and the glass is a high refractive index transparent material that can meet the condition of total internal reflection, which can well confine the light transmission in the waveguide, and the light can be transmitted in the waveguide with low loss and high efficiency by using the principle of total internal reflection.

[0097] The nanometer imprinting technology is used to manufacture surface relief gratings on both sides of the glass planar optical waveguide substrate to form the in-coupling grating 7-1 and the out-coupling grating 7-3, and by adjusting the grating period, depth and other parameters, the coupling efficiency and angle can be optimized.

[0098] In this embodiment, the light receiving part 8 is a human eye, and in actual application, the light receiving part 8 further includes a screen and an image sensor.

[0099] Working principle:

[0100] The micro projection system based on the single-chip Micro LED micro display array chip is controlled by an external system connected through a reserved micro display array driving interface, a driving circuit is connected with the Micro LED micro display array chip through a through-hole electrode on the back of the substrate, and each pixel is controlled; the green Micro LED micro display array chip 2, the red Micro LED micro display array chip 3 and the blue Micro LED micro display array chip 4 generate images of respective colors; each Micro LED micro display array chip contains a large number of tiny LED pixels, and the brightness of each pixel can be independently controlled. Each micro display array chip is attached to or mounted on an incident prism of a corresponding color, green light enters the green light incident prism 1-1, passes through the green light reflecting film and the blue light reflecting film, and reaches the light-emitting prism 1-4; red light enters the red light incident prism 1-2, passes through the green light reflecting film and the blue light reflecting film, and enters the light-emitting prism 1-4; blue light enters the blue light incident prism 1-3, passes through the blue light reflecting film and the green light reflecting film, and enters the light-emitting prism 1-4; at the light-emitting prism 1-4, the red, green and blue three-color images are accurately overlapped to form a complete color image, and finally output from the light-emitting prism 1-4; the light projection part 5 located outside the light-emitting prism 1-4 receives the synthesized color image and projects it onto the target surface.

[0101] The above description is only the preferred embodiment of the present application, and is not used to limit the present application, any modification, equivalent replacement and improvement within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A Micro LED microdisplay array chip, characterized in that, The microstructure includes a substrate (2-1), a buffer layer (2-2) on the upper surface of the substrate (2-1), a common N-type highly doped conductive layer (2-3) on the upper surface of the buffer layer (2-2), an N-type electron injection layer (2-4) on the upper surface of the common N-type highly doped conductive layer (2-3), a multi-quantum well active region (2-5) on the upper surface of the N-type electron injection layer (2-4), a P-type hole injection layer (2-6) on the upper surface of the multi-quantum well active region (2-5), and a transparent electrode layer (2-7) on the upper surface of the P-type hole injection layer (2-6). The LED microdisplay array chip consists of an insulating layer (2-8) between the upper surface of the common N-polar highly doped conductive layer (2-3) at both ends and a single pixel, a common P-polar contact electrode (2-9) at both ends of the transparent electrode layer (2-7), a common P-polar metal conductive layer (2-10) filling the lower surface of the common P-polar contact electrode (2-9) and passing through the P-polar via of the substrate (2-1) and the insulating layer (2-8), a common P-polar via electrode (2-11) at the lower surface of the common P-polar metal conductive layer (2-10), a common N-polar metal conductive layer (2-12) filling the lower surface of the common N-polar highly doped conductive layer (2-3) at both ends and passing through the N-polar via of the buffer layer (2-2) and the substrate (2-1), a common N-polar via electrode (2-13) at the lower surface of the common N-polar metal conductive layer (2-12), and a light-transmitting protective layer (2-14) grown on the upper surface of the array.

2. A micro-projection system based on a monolithic Micro LED microdisplay array chip, characterized in that, include: A cube-shaped color-combining prism group (1) is composed of four independent triangular prisms, namely a green light incident prism (1-1), a red light incident prism (1-2), a blue light incident prism (1-3), and a light-emitting prism (1-4). The Micro LED microdisplay array chip of claim 1, wherein the Micro LED microdisplay array chip is mounted on the light-incident surface of the color-combining prism group (1), and the microdisplay array chip includes a green Micro LED microdisplay array chip (2) mounted on the light-incident surface of the green light incident prism (1-1), a red Micro LED microdisplay array chip (3) mounted on the light-incident surface of the red light incident prism (1-2), and a blue Micro LED microdisplay array chip (4) mounted on the light-incident surface of the blue light incident prism (1-3); The light projection section (5) is located outside the light-emitting surface of the color-combining prism group (1) and coincides with the optical axis of the light-emitting prisms (1-4); wherein: The green Micro LED microdisplay array chip (2), red Micro LED microdisplay array chip (3), and blue Micro LED microdisplay array chip (4) have integrated monolithic processing of their Micro LED pixel arrays. The pixel arrays use a common original LED substrate without single-pixel cutting or separation. The substrate is prepared with a common N-electrode highly doped conductive layer (2-3) through epitaxial growth. Row pixels share the common N-electrode highly doped conductive layer (2-3) as a common N electrode, and column pixels use a transparent electrode layer (2-7) as a common P electrode. A common P contact electrode (2-9) is led out from the common P electrode, and the microdisplay array emits light through the transparent electrode layer (2-7). The buffer layer (2-2) of the Micro LED microdisplay array chip is etched to the substrate (2-1) along with the common N-electrode highly doped conductive layer (2-3) and has the same etching shape.

3. The micro-projection system based on a single Micro LED micro-display array chip according to claim 2, characterized in that, A common N-hole electrode (2-13) is fabricated on the back side of the substrate (2-1) of the microdisplay array chip at the position corresponding to the common N-electrode lead-out point, and a common P-hole electrode (2-11) is fabricated at the position corresponding to the common P-contact electrode (2-9) lead-out point. The row and column scanning electrodes form a microdisplay array driving interface through the through-hole electrodes on the back side of the substrate.

4. The micro-projection system based on a monolithic Micro LED micro-display array chip according to claim 2, characterized in that, The green Micro LED microdisplay array chip (2), the red Micro LED microdisplay array chip (3), and the blue Micro LED microdisplay array chip (4) have the same geometric dimensions and are provided with image alignment pattern (2-15) and array optical path alignment pattern (2-16) on their surfaces.

5. The micro-projection system based on a single Micro LED micro-display array chip according to claim 2, characterized in that, The light incident surfaces of the green light incident prism (1-1), red light incident prism (1-2), and blue light incident prism (1-3) are provided with prism optical path alignment patterns (1-5).

6. The micro-projection system based on a monolithic Micro LED micro-display array chip according to claim 2, characterized in that, The red light incident prism (1-2) is located between the green light incident prism (1-1) and the blue light incident prism (1-3). A green light reflective film is provided on the mating surface of the green light incident prism (1-1) and the red light incident prism (1-2); a blue light reflective film is provided on the mating surface of the red light incident prism (1-2) and the blue light incident prism (1-3); a blue light reflective film is provided on the mating surface of the green light incident prism (1-1) and the light output prism (1-4); and a green light reflective film is provided on the mating surface of the blue light incident prism (1-3) and the light output prism (1-4).

7. The micro-projection system based on a monolithic Micro LED micro-display array chip according to claim 2, characterized in that, The green light incident prism (1-1) is located between the red light incident prism (1-2) and the blue light incident prism (1-3). A red light reflective film is provided on the mating surface of the red light incident prism (1-2) and the green light incident prism (1-1); a blue light reflective film is provided on the mating surface of the green light incident prism (1-1) and the blue light incident prism (1-3); a blue light reflective film is provided on the mating surface of the red light incident prism (1-2) and the light output prism (1-4); and a red light reflective film is provided on the mating surface of the blue light incident prism (1-3) and the light output prism (1-4).

8. The micro-projection system based on a monolithic Micro LED micro-display array chip according to claim 2, characterized in that, The blue light incident prism (1-3) is located between the green light incident prism (1-1) and the red light incident prism (1-2). A red light reflective film is provided on the bonding surface of the red light incident prism (1-2) and the blue light incident prism (1-3); a green light reflective film is provided on the bonding surface of the blue light incident prism (1-3) and the green light incident prism (1-1); a green light reflective film is provided on the bonding surface of the red light incident prism (1-2) and the light output prism (1-4); and a red light reflective film is provided on the bonding surface of the green light incident prism (1-1) and the light output prism (1-4).

9. The micro-projection system based on a monolithic Micro LED micro-display array chip according to any one of claims 6-8, characterized in that, The green light reflective film reflects green light and transmits blue and red light; the blue light reflective film reflects blue light and transmits red and green light; the red light reflective film reflects red light and transmits blue and green light; the color combining prism group (1) coincides with the optical axis of the light projection unit (5); the full-color image output by the light output prism (1-4) is output to the display area by the light projection unit (5).

10. A fabrication process for a micro-projection system based on a monolithic Micro LED microdisplay array chip, characterized in that, include: S1. The green Micro LED micro display array chip (2), the red Micro LED micro display array chip (3), and the blue Micro LED micro display array chip (4) are respectively mounted on the light-incident surfaces of the green light incident prism (1-1), the red light incident prism (1-2), and the blue light incident prism (1-3) according to the array light path alignment pattern (2-16) on the Micro LED micro display array chip and the prism light path alignment pattern (1-5) on the incident prism. S2. A green light reflective film is provided on the bonding surface of the green light incident prism (1-1) and the red light incident prism (1-2); a blue light reflective film is provided on the bonding surface of the red light incident prism (1-2) and the blue light incident prism (1-3); a blue light reflective film is provided on the bonding surface of the green light incident prism (1-1) and the light output prism (1-4); a green light reflective film is provided on the bonding surface of the blue light incident prism (1-3) and the light output prism (1-4). Alternatively, a red light reflective film may be provided on the bonding surface of the red light incident prism (1-2) and the green light incident prism (1-1); a blue light reflective film may be provided on the bonding surface of the green light incident prism (1-1) and the blue light incident prism (1-3); a blue light reflective film may be provided on the bonding surface of the red light incident prism (1-2) and the light exiting prism (1-4); and a red light reflective film may be provided on the bonding surface of the blue light incident prism (1-3) and the light exiting prism (1-4). Alternatively, a red light reflective film may be provided on the bonding surface of the red light incident prism (1-2) and the blue light incident prism (1-3); a green light reflective film may be provided on the bonding surface of the blue light incident prism (1-3) and the green light incident prism (1-1); a green light reflective film may be provided on the bonding surface of the red light incident prism (1-2) and the light exiting prism (1-4); and a red light reflective film may be provided on the bonding surface of the green light incident prism (1-1) and the light exiting prism (1-4). S3. A color-combining prism group (1) is formed by combining a green light incident prism (1-1), a red light incident prism (1-2), a blue light incident prism (1-3), and an output prism (1-4) with a Micro LED micro-display array chip and a reflective film attached. The positions of the green light incident prism (1-1), the red light incident prism (1-2), the blue light incident prism (1-3), and the output prism (1-4) are adjusted according to the image alignment marks of the Micro LED micro-display array chip so that the green, red, and blue images output by the output prism (1-4) overlap. S4. Complete the fixation of the green Micro LED micro display array chip (2), the red Micro LED micro display array chip (3), the blue Micro LED micro display array chip (4) and the color-combining prism group (1); S5. Adjust the lens position of the light projection unit (5) so that the output image of the light prism (1-4) and the light projection unit (5) are on the same optical axis; S6. Reserve a display array driving interface and encapsulate the green Micro LED micro display array chip (2), the red Micro LED micro display array chip (3), the blue Micro LED micro display array chip (4), the color combining prism group (1), and the light projection part (5) to form a micro projection system.

Images